The present invention relates to electrical distribution load centers, panelboards, and the like, which have modular interior components providing a more compact design.
Load centers distribute power for residential, commercial and light-industrial applications. A load center usually provides a mounting enclosure and incorporates an insulating base to carry an incoming line neutral bar for each phase and a ground bar. Individual circuit breakers are mounted to these devices to protect branch circuits against overload and fault conditions. The interior assembly of the load centers are often constructed with bus bars or projecting lugs to form disconnect contacts for the removable individual circuit breakers.
The need arises to distribute more power through enclosures which are the same size or smaller. This requires increasing the electrical rating of the load center to carry a higher voltage and current density while decreasing the size of the enclosure housing the electrical parts.
Among the problems caused by decreasing the space requirements of a load center is the additional hardware necessary for mounting different types of circuit breakers, neutral bars, bus bars, and other components in the load center. Usually, only one type of circuit breaker will fit with a particular bus bar or other components. Furthermore, mounting screws are used to attach and retain these components to the load center interior. The need arises to assemble load centers with increasingly smaller enclosures providing little room for maneuvering. This requires electrical components which can be assembled without complicated tools, or preferably, without any tools.
Other problems caused by assembling the load center interiors is the quantity of parts that must be tracked, inventoried, and supplied in the field to properly complete the assembly. A reduced part count and less manual labor during assembly would decrease installation time and cost.
Furthermore, the parts for the load center interior must be economical to manufacture. A load center which assembles easier and faster at a comparable cost allows more wide-spread application.
Accordingly, the present invention provides an interior assembly for an electrical distribution device. The interior assembly having at least one bus bar and neutral bar connecting the electrical distribution device to a circuit having at least one phase. The neutral bar and bus bar having a bottom wall and side walls. The support base includes a generally planar body defining a mounting surface on one face of the body and means for mounting the bus bar on the mounting surface. The support base also includes means for retaining the bottom wall of the neutral bar abutting the mounting surface of the body. The retaining means is manually operated and integrally formed with the mounting surface and has a plurality of projections upstanding from the mounting surface. The projections are adapted to abut the side walls of the neutral bar so as to prevent movement in at least one direction horizontally. The retaining means also has at least one interlocking prong for abutting one or more side walls of the neutral bar so as to prevent movement in the vertical direction and the remaining horizontal directions.
Another aspect of the present invention is a neutral base for an interior assembly of an electrical distribution device. The interior assembly having a surface for mounting at least one bus bar. The neutral base connects the electrical distribution device to a circuit having at least one phase. The neutral base includes a generally rectangular body having a mounting surface and a neutral bar for making an electrical connection. The neutral bar has a bottom wall for abutting the mounting surface of the body and side walls. Means for retaining the neutral bar abutting the mounting surface of the body is included. The retaining means is manually operated and integrally formed with the body. Means for securing the body to the mounting surface of the interior assembly is also included so that the mounting surface of the body is in the same plane as and abutting the mounting surface of the interior assembly, the securing means being integrally formed with the body.
The present invention also includes an interior assembly of an electrical distribution device assembled by upstanding a plurality of projections from the mounting surface; abutting the side walls of the neutral bar against the projections so as to prevent movement in at least one direction horizontally; upstanding at least one interlocking prong from the mounting surface, each interlocking prong having an undercut between the mounting surface and the end of the prong to define a retaining flange; abutting one or more side walls of the neutral bar with the interlocking prong so as to prevent movement in the vertical direction and the remaining horizontal directions; and, manually inserting without discrete fasteners the neutral bar between the upstanding projections and the interlocking prong to rest on the mounting surface of the interior assembly.
An object of the present invention is to provide a load center interior assembly which reduces the part count, the need for discrete fasteners, and the labor content needed for a completed assembly compared to the prior art.
Another object of the present invention is to provide a load center assembly with modular components such as a neutral bar which assemble with a minimum of tools.
Still another object of the present invention is to provide a load center capable of operating at a comparable voltage and current density having a more compact design.
A further object of the present invention is to provide a load center which is inexpensive to manufacture and accommodates a variety of circuit breaker types and quantities without additional hardware for installation.
Another object of the invention is to provide individual components of a load center assembly such as a neutral bar that have mounting features integrally formed therewith and snap-together to reduce riveting and preening of parts.